Pleuronema grolierei Wang et al., 2008

Jung, Jae-Ho, 2021, Taxonomy of four scuticociliates (Protozoa: Ciliophora) from coastal waters of South Korea, Journal of Species Research 10 (2), pp. 184-190 : 186-187

2. Pleuronema grolierei Wang et al., 2008 ( Fig. 2 )

Material examined. Coastal water sample (25.4‰, 21.0℃) collected from Yeosu-si, Jeollanam-do, Republic of Korea (34°2′50″N, 127°17′33″E) on 10 July 2019 ; coastal water sample (33.5‰, 14.5℃) collected from Pohangsi , Gyeongsangbuk-do, Republic of Korea (36°3′2.9″N, 129°22′22.3″E) on 23 November 2020 .

Diagnosis (n = 5). Cell size 40.2-53.2 × 15.8-19.6 μm (47.2 × 17.7 μm on average) in protargol preparations, outline slightly oval to spindle-like, dorsoventrally flattened; 1 globular to elliptical macronucleus, 7.8-12.1 × 7.7-9.7 μm (10.5 × 8.3 μm on average) in size; 1 globular micronucleus attached to macronucleus; 1 or 2 preoral kineties (note that 1 out of 5 specimens showed 2 preoral kineties and 1 postoral kinety might have resulted from a fragmentation of somatic kinety 1), 24-26 somatic kineties, prolonged caudal cilia; buccal area occupying 67.1- 74.4% (70.4% on average) of body length; paroral membrane conspicuous, hook or ‘6’-shaped; M1 three-rowed; M1:M2a length ratio about 40%, M2a more or less straight without conspicuous structure at posterior end (i.e., ring-like, hook-like structure), 12.0-16.4 μm in length; M2b V-shaped; M3 two-rowed.

Distribution. China ( Wang et al., 2008a; Pan et al., 2015b) and Korea (this study).

Remarks. Pleuronema grolierei resembles P. arenicola Dragesco, 1960 , but the former can be distinguished by the inconspicuous paroral membrane (vs. conspicuous), one preoral kinety (vs. 3), and completely two-rowed M2a (vs. two-rowed only in posterior part) ( Dragesco, 1960; Wang et al., 2008a; Pan et al., 2015b). The Korean population differs from the Chinese population (type population) by body length (40.2-53.2 μm vs. 56-71 μm), but this size variation was also observed in Pleuronema species ( Borror, 1963; Dragesco and Dragesco-Kernéis, 1986; Agatha et al., 1993; Song, 2000).

Voucher slides. Three slides with protargol-impregnated specimens were deposited at the National Marine Biodiversity Institute of Korea (GUC002230-2231, Yeosu population) and the National Institute of Biological Resources, Korea (NIBRPR0000110213, Pohang population).

Figures

Fig. 2. Pleuronema grolierei after protargol impregnation. A, C. Ventral views showing a typical body shape and infraciliature. B. Dorsal view showing somatic kineties. D. Nuclear apparatus, arrow denotes a micronucleus. CC, caudal cilia; Ma, macronucleus; M1, 3, membranelles 1, 3; M2a, anterior part of membranelle 2; M2b, posterior part of membranelle 2; PM, paroral membrane; PK; preoral kineties; PoK, postoral kinety; SK, somatic kineties. Scale bar=30 μm.